The present invention relates to a new and improved computerized method for task management and, more particularly, it relates to a computerized method for task management of synthetic fiber spinning machine operators.
During normal operation of synthetic fiber spinning machines, polymer is conveyed from a polymerization vessel and extruded through a spinneret to form a group of filaments which are conveyed to a windup and wound on bobbins to form yarn packages. Often, operations such as drawing, relaxing and heat treating the yarn are performed between the spinneret and the windup. Commonly, the group of advancing filaments is split into individual "ends", with each end forming a separate yarn package.
A variety of operations are performed by operators on such spinning machines. A very important operation referred to as "doffing" involves removal of a package from the windup and restringing the advancing end onto a fresh bobbin.
Doffing is a task performed in response to a variety of events, for example a scheduled doff occurs when a package is full or when maintenance tasks (e.g., wiping residues from the spinneret face or changing equipment such as the spinning pack) must be performed; an unscheduled doff occurs when a threadline breaks.
These events requiring operator tasks do not always occur in an ordered, planned manner. Frequently two or three events occur in rapid succession or simultaneously or on opposite sides of a spinning machine and not only cause confusion and consternation on the part of the operator (or teams of operators) but result in inefficient operation at times, causing costly waste. Another deleterious result is production of off-size yarn packages which are very difficult for fabric producers to use efficiently.
Many systems have been proposed to overcome some of the disadvantages of this state of affairs. In one system the operator presses a button after restringing a position to signal a computer to activate a light indicating need to doff at a preset time at a specific position. Unfortunately, many times the operator does not see the light, especially if he is on the other side of the machine. Systems are known which use an electronic sensor to determine the presence or absence of threadlines at a given windup position (hereinafter termed "position"). The sensor signal is input to a computer to produce information on status of each position; i.e., whether or not it is winding fiber, and a specific time schedule for doffing each position. In some systems the information is displayed on a computer-driven display for ready viewing by operators. The latter system has several deficiencies. Use of a single sensor per position does not provide reliable enough information to distinguish between the various possible states of each position; i.e., (a) winding fiber (referred to as the "Run State"), (b) not winding fiber because it is being doffed (referred to as the " Doff State"), (c) not winding fiber due to a threadline break (referred to as the "Down State"). Further complications occur such as giving misleading information when the sensor itself fails (a common occurrence).